R&S ZVB - Page 353

R&S
®
ZVA / R&S
®
ZVB / R&S
®
ZVT GUI Reference
Channel Menu
Operating Manual 1145.1084.12 – 30 338
- for network analyzers R&S ZVT connected to an Extension Unit R&S ZVAX-TRM with installed
combiner option
- for network analyzers R&S ZVT20 that are equipped with option R&S ZVT20-B11
With internal combiner, the two-tone signal is available at port 1.
 The settings in the Receiver panel define the bandwidth and selectivity of the IF filter at test port 2.
 Measurement Setup opens the Mixer Delay Measurement Setup dialog for selection and
configuration of a test setup with an additional R&S ZVA network analyzer, to be used as an
external receiver.
 Define Mixer Measurement opens the configuration dialog for a scalar mixer measurement. Use
this dialog to select the LO source port and to define port frequencies and power levels.
 Set Frequencies and Powers... opens a dialog to define the sweep range.
Selecting appropriate apertures and meas. bandwidths
The mixer delay measurement depends on the frequency difference between the upper and lower tone
termed the Aperture. Conversion of the two-tone RF signal in the mixer preserves the aperture. To ensure
that the analyzer can detect the two IF signals and calculate reasonable group delay results, observe the
following rules:
 Select a measurement bandwidth (IF bandwidth) which is significantly smaller than the aperture.
High selectivity IF filters have steeper edges and improve the detection of the two adjacent
signals.
 Detection fails if the frequency drift of the LO is larger than the IF bandwidth. An IF bandwidth
larger than approx. 3 times the maximum LO drift is generally sufficient.
 The aperture must be adjusted to the mixer properties. A small aperture increases the noise in the
group delay; a large aperture tends to minimize noise, but at the expense of the frequency
resolution. Large aperture settings are preferable if the mixer shows little dispersion (i.e. almost
constant delay).
For most broadband mixers, large aperture values (10 MHz to 15 MHz) are preferable. For
satellite applications, smaller apertures (2 MHz to 4 MHz) are recommended. See also Trace –
Format – Aperture.
 The calculation of the mixer delay fails if the phase shift difference between the upper and lower
tones caused by the mixer exceeds 180 deg.
Primed wave quantities
When a mixer delay measurement is active, the wave quantities a and b in the More Wave Quantities and
More Ratios dialogs correspond to the lower tone. The primed wave quantities a' and b' correspond to the
upper tone.
Remote control:
[SENSe<Ch>:]FREQuency:MDELay:UTONe
[SENSe<Ch>:]FREQuency:MDELay:APERture
[SENSe<Ch>:]FREQuency:MDELay:COMBiner[:STATe]
[SENSe<Ch>:]BANDwidth|BWIDth[:RESolution]
[SENSe<Ch>:]BANDwidth|BWIDth[:RESolution]:SELect
[SENSe<Ch>:]FREQuency:MDELay:CORRection[:STATe]